1. Field of the Invention
The present invention relates generally to the field of iron-binding glycoproteins. More specifically, the present invention relates to the recombinant production of human lactoferrin.
2. Description of the Related Art
Human lactoferrin (LF) is a member of the transferrin family of iron-binding monomeric glycoproteins. It was originally discovered in milk where it can reach levels of 7 grams/liter in colostrum. LF has since been detected in other external fluids such as tears, saliva and mucosal secretions and also in the secondary granules of polymorphonuclear leukocytes.
LF is a 78 kDa glycoprotein having a bilobal structure with a high degree of homology between the C and N terminal halves which is evident at both the amino acid and three dimensional structural level. Each of these lobes can reversibly bind one ferric iron with high affinity and with the concomitant binding of bicarbonate. The biological functions proposed for lactoferrin include protection against microbial infection, enhanced intestinal iron absorption in infants, promotion of cell growth, regulation of myelopoiesis and modulation of inflammatory responses.
Filamentous fungi have been successfully employed as hosts in the industrial production of extracellular glycoproteins. Certain industrial strains are capable of secreting gram quantities of these proteins. In addition, filamentous fungi are able to correctly perform post-translational modifications of eucaryotic proteins and many strains have U.S Food and Drug Administration approval. Furthermore, large scale fermentation technology and downstream processing experience is available.
Currently, there is no efficient and economical way to produce human LF. Consequently, a long felt need and description in this art would be met by the development of an efficient method for the production of human lactoferrin for nutritional and therapeutic applications and for further investigation into its mechanism of action.